Field of the Invention
The present invention relates to a display apparatus having a plurality of semiconductor switching elements.
Description of the Background Art
In recent years, individual elements to constitute display apparatuses have been smaller or more precise. Further, the market has seen a growing need for an improvement in quality of the display apparatuses. Specifically, the market has seen an increasingly strict need for the improvement in quality where a display apparatus with only one bright spot detect (a pixel that is always bright) is judged to be a defective. Such a need unfortunately reduces productivity of the display apparatuses.
To meet the need for the improvement in quality and enhance the productivity, repairing bright spot defects to be black spot defects (pixels that are always dark) is currently used for an effective way to reduce the bright spot defects.
For instance, reference is made to an array of a twisted nematic (TN) structure. Disclosed is a method of repairing a target pixel to be always a black spot by irradiating, with a laser, a location where a gate wire and a pixel electrode overlap with each other in a plan view and by short-circuiting (fusing) the gate wire and the pixel electrode, thus to always put a gate potential into the pixel electrode (e.g., see Japanese Patent Application Laid-Open No. 05-249488).
Further, reference is made to an array of an in-place-switching structure (hereinafter, referred to as an in-place-switching mode). Disclosed is a method of repairing a target pixel to be a black spot by irradiating, with a laser, a location where a common wire and a pixel electrode overlap with each other in a plan view and by short-circuiting (fusing) the common wire and the pixel electrode, thus to always put a common potential into the pixel electrode (e.g., see Japanese Patent Application Laid-Open No, 2009-151094).
In response to a need for a further improvement in display quality, the use of the in-place-switching mode having excellent view angle characteristics and a fringe-field-switching (FFS) mode capable of improving an effective aperture ratio for lower power consumption has been recently increasing.
A display apparatus that uses the in-place-switching mode and the FFS mode has normally-black display characteristics. Accordingly, it is possible to change the bright spot defect to the black spot by causing the pixel electrode and the common electrode to have the same potential. To achieve such a change to the black spot, one known repair method includes connecting the pixel electrode and the common electrode in a perspective view by irradiating, with a laser, an area where the pixel electrode and the common electrode overlap with each other in a plan view.
However, a transparent electrode of, for example, indium tin oxide (ITO) is often used as the pixel electrode and common electrode in an array structure that uses the in-place-switching mode and the FFS mode. Although ITOs need to be connected to each other for repair, they are hard to be connected with the laser (a stable connection with a low resistance is impossible). This unfortunately degrades the stability of the repair.
To avoid such a connection of the ITOs, one method includes disposing, in advance, metal thin films for repair separately connected to the ITOs used as the pixel electrode and the ITO used as the common electrode, respectively, and then connecting the metal thin films for repair to each other with the laser when a repair is necessary. This method enhances the stability of the repair, but unfortunately decreases an aperture ratio of an array substrate due to the disposal of the metal thin films, which do not contribute to the constitution of the display apparatus, thus resulting in more power consumption.